In recent years, hold display apparatuses including liquid crystal display modules and/or EL display modules have gone into use in a field where CRTs (cathode-ray tubes) have been used.
However, it is said that such a hold display apparatus is inferior in quality of a moving image to an impulse display apparatus, such as a CRT (cathode-ray tube), in which an ON period during which an image is displayed and an OFF period during which no image is displayed are alternately repeated.
That is, in a typical hold display apparatus, the whole of one frame period corresponds to an ON period, so  that an update of a frame image causes the subject to be displayed as if the subject stays in the previous position until the image is updated for the next frame. This appears as image blur to the eyes of an observer.
Conventionally, there has been proposed a sub-frame display method, having as an object to improve such a quality of a moving image, which drives a plurality of sub-frames into which a frame that displays one image has been time-divided. Examples of such a sub-frame display method are disclosed in Patent Documents 1 to 4.
Meanwhile, a display screen has conventionally been divided in a vertical direction into an upper-screen region and a lower-screen region in each of which display scanning is independently carried out. Examples of this are disclosed in Patent Documents 5 and 6.
[Patent Document 1]
Japanese Unexamined Patent Application Publication No. 302289/1992 (Tokukaihei 4-302289; published on Oct. 26, 1992)
[Patent Document 2]
Japanese Unexamined Patent Application Publication No. 281625/2001 (Tokukai 2001-281625; published on Oct. 10, 2001)
[Patent Document 3]
Japanese Unexamined Patent Application Publication  No. 23707/2002 (Tokukai 2002-23707; published on Jan. 25, 2002)
[Patent Document 4]
Japanese Unexamined Patent Application Publication No. 22061/2003 (Tokukai 2003-22061; published on Jan. 24, 2003)
[Patent Document 5]
Japanese Unexamined Patent Application Publication No. 268261/1998 (Tokukaihei 10-268261; published on Oct. 9, 1998)
[Patent Document 6]
Japanese Unexamined Patent Application Publication No. 297564/1997 (Tokukaihei 9-297564; published on Nov. 18, 1997)
However, as compared with a case where a frame is not divided into sub-frames (a case of a normal hold display carried out by turning on all gate lines of a liquid crystal panel only once in one frame period), a sub-frame display carried out by driving a plurality of sub-frames into which a frame has been divided causes a reduction in time during which the voltage of an image signal is applied to a pixel.
For this reason, the voltage of an image signal cannot be sufficiently applied to a pixel due to lack of pixel charging time. This causes deterioration in display  quality, and makes it impossible to increase the number of sub-frames (into which a frame is divided).
The present invention has been made in view of the foregoing problems, and it is an object of the present invention to provide a display apparatus in which sufficient pixel charging time can be obtained even when sub-frames into which a frame has been time-divided are driven.